Hacktoberfest: Program to calculate count of vowels & consonants in string

//Program to calculate count of vowels & consonants in string

#include<stdio.h> 
#include<string.h> 
#include<ctype.h>

int main()  
{  
   int i, vowels= 0, consonant = 0;  

   char str[] = "A compiler is a special program that processes statements written in a particular programming language and turns them into machine language or code that a computer's processor uses.";

   for(i = 0; i < strlen(str); i++){  
       str[i] = tolower(str[i]);  
       if(str[i] == 'a' || str[i] == 'e' || str[i] == 'i' || str[i] == 'o' || str[i] == 'u') {  
            vowels++;  
        }  
        else if(str[i] >= 'a' && str[i] <= 'z'){  
            consonant++;  
        }  
   }  
  
   printf("Number of vowels are : %d\n", vowels);  
   printf("Number of consonant are: %d", consonant);  
   
   return 0;  
}